History and Anatomy of the Microscope

History of Microscopy

• Zacharias Jansen invented the first compound microscope around 1590.
• Anton Van Leeuwenhoek made significant improvements to the compound microscope in the mid-1600s.
• Robert Hooke used a compound microscope to observe "cells" in cork.
• Joseph Jackson Lister developed the first prototype of a compound microscope which reduced spherical aberration.
• Richard Zsigmondy developed the ultramicroscope.
• Frits Zernike invented the phase-contrast microscope.
• Ernst Ruska (with Knoll) co-invented the electron microscope.
• Gerd Binnig and Heinrich Rohrer invented the scanning tunneling microscope.

Compound Microscope

• Arm supports the body tube and connects to the base, used for carrying the microscope.
• Base provides support to all other parts of the microscope.
• Body Tube hollow tube where light passes through from the eyepiece to the revolving nosepiece.
• Coarse Adjustment Knob large knob used for focusing, typically with the low-power objective lens.
• Diaphragm controls the amount of light passing through the specimen, affects how much light enters the body tube.
• Condenser collects and focuses illuminator's light onto the specimen, located under the stage with an iris diaphragm.
• Eyepiece or Ocular Lens allows viewing the object and magnifies the image 10 times.
• Fine Adjustment Knob small knob used to move the body tube for focusing the high-power lens for larger magnification.
• Objective Lenses lenses with different magnifications:
  • Scanning objectives magnify the image on the slide, usually 2x or 4 times.
  • Low Power Objective magnifies the image on the slide, usually 10 times.
  • High Power Objective magnifies the image on the slide, usually 40 times or higher.
  • Oil Immersion Objective uses a special oil and magnifies the image on the slide, usually 100x.
• Lamp/Mirror reflects light through the sample.
• Revolving Nosepiece holds the objectives and allows for changing the magnification.
• Stage flat surface where slides are placed.
• Stage Clips hold slides in place.

Types of Microscopes

• Light Microscope uses visible light and a lens system to magnify images, magnifies up to 500x.
  • Simple Microscope uses a single convex lens for magnification.
  • Compound Light Microscope uses two lenses (ocular and objective) for up to 2000x magnification.
  • Standard Compound Light Microscope uses two lenses, with the eyepiece lens in line with the revolving nosepiece.
• Electron Microscope uses a beam of electrons with short wavelengths, observes specimens at nanometer size.
  • Transmission Electron Microscope (TEM) produces images of one-nanometer size, used to study cells.
  • Scanning Electron Microscope (SEM) less powerful than TEM, produces high-resolution 3D images.
  • Reflection Electron Microscopy (REM) uses an electron beam to detect elastically scattered electrons.

Focusing a Microscope

• Start with the lowest power objective lens.
• While looking from the side, lower the lens as close to the specimen as possible without touching it.
• Look through the eyepiece and focus upward until the image is sharp.
• Once the image is sharp with the low-power lens, click in the next power lens and make minor adjustments with the fine adjustment knob.
• Continue this process with each subsequent objective lens, fine tuning the focus each time.
• Keep both eyes open while viewing to prevent eye fatigue.
• Never touch the ocular lens with your eyelashes.
• Remove eyeglasses when viewing to avoid scratches.

Basic Rules for Microscope Care

• Hold the microscope by the arm with one hand, supporting the base with the other. Never grab by the eyepiece holder.
• Turn off the illuminator when not in use.
• Clean the stage and lenses before putting the microscope away.
• Use good quality lens tissue on optical surfaces.
• Clean the oil immersion objective immediately after use.
• Focus smoothly, do not rush or force anything.
• If the microscope isn't working, do not attempt to fix it unless you know what you are doing.
• Cover the microscope with a dust jacket when not in use.
• Keep the microscope in a clean, dry place.

Explore the fascinating evolution of microscopy from its inception with Zacharias Jansen to modern advances like the electron microscope. This quiz covers key inventors and essential components of compound microscopes, shedding light on the technological advancements that have shaped scientific exploration.